Background: The Extracorporeal Life Support Organization (ELSO) Maastricht Treaty for Nomenclature in Extracorporeal Life Support (ECLS) established consensus nomenclature and abbreviations for ECLS to ensure accurate, concise communication. Methods: We build on this consensus nomenclature by layering a framework of precise and efficient abbreviations for cannula configuration that describe flow direction, number of cannulae used, any additional ECLS-related catheters, and cannulation sites. This work is a consensus of international representatives of the ELSO, including those from the North American, Latin American, European, South and West Asian, and Asian-Pacific chapters of ELSO. Results: The classification increases in descriptive capability by introducing a third (cannula tip position) and fourth (cannula dimension) level to those provided in the previous consensus on ECLS cannulation configuration nomenclature. This expansion offers the simplest level needed to convey cannulation information yet allows for more details when required. Conclusions: A complete nomenclature for ECLS cannulation configurations accommodating future revisions was developed to facilitate ability to compare practices and results, to promote efficient communication, and to improve quality of registry data. © 2019 The Author(s).